Telecommunication networks transport voice and data according to a variety of standards and using a variety of technologies. Circuit-switch networks such as plain old telephone service (POTS) utilize transmission paths dedicated to specific users for the duration of a call and employ continuous, fixed-bandwidth transmission. Packet-switch networks (PSNs) allow dynamic bandwidth, depending on the application, and can be divided into connectionless networks with no dedicated paths and connection-oriented networks with virtual circuits having dedicated bandwidth along a predetermined path. Because packet-switched networks allow traffic from multiple users to share communication links, these networks utilize available bandwidth more efficiently than circuit-switched networks.
Internet protocol (IP) networks are connectionless packet-switched networks. IP networks transport information by breaking up bitstreams into addressable digital packets. Each IP packet includes source and destination addresses and can take any available route between the source and the destination. The IP packets are transmitted independently and then reassembled in the correct sequence at the destination.
Conventional IP networks employ routers to direct packets to their destination. Packets are inspected at each router for network protocol addresses and forwarded to a next router on the way toward the destination based on downstream congestion and other real-time parameters. While this inspection and dynamic routing provides a high degree of flexibility within the network, it adds delays to each packet at each router. Accordingly, traffic transported across an IP network between geographically distributed source and destination points will have a relatively large cumulative delay. This limits the ability of the IP network to support voice, video, and other real-time applications.